This invention relates to a pneumatic tire and, more particularly, to a tubeless pneumatic tire having means for preventing air retention when the tire is mounted on a wheel having a rim diameter smaller than that for which it was designed.
Pneumatic tire come in a variety of sizes and are generally designed to be used with a particular wheel size. When a tire is mounted and inflated on the size wheel for which it was designed, the bead portions of the tire engage the bead seats and rim flanges of the wheel in a secure manner, forming an airtight seal between the bead portion of the tire and the bead seat of the rim. Proper bead seating is essential in a tubeless-type tire from the standpoint of tire performance and safety of the occupants of a vehicle on which the tires are mounted.
With the large selection of tubeless tire and wheel sizes, there exists the possibility that a tire may be incorrectly mounted on a wheel having a rim diameter slightly smaller than that for which it was designed. Although the bead portions of the tire will not properly seal, inflation of the tire may occur due to the sealing engagement of the axial outer surface of the bead portions of the tire with the flanges of the rim. However, this type of sealing engagement is insecure and may lead to premature failure of the tire, thus, causing possibly injury to the occupants of the vehicle and/or damage to the tire itself. This type of mismounting is, of course, limited to wheels having a rim diameter smaller than that for which the tire was designed, but large enough to permit sealing between the rim flange and side of the bead portion of the tire.